Previously stencila would not install under python 3.
Python35 is the default Python version.
I opened a command window and ran
C:\PYTHON27\SCRIPTS\virtualenv ENV and then activate.bat
Python27 is now the default python .
Started C:\Users\PlantGRIN\AppData\Local\Programs\stencila-desktop\Stencila.exe
Py() still has a red to over code blocks.